Who is Right?

When I talk with my friends, somewhat the topic gets deviated from Physics to Philosophy. I am a lot used to relate physics with philosophy. But my friend is good at pure philosophy.

         

We were discussing about Relativity and the concept of reality. I said the Physical reality is not true. Everything we observe in our real life is not the absolute truth. But it is only true with respect to someone or something. The concept of absolute can never be reached.

         

The world of a blind will be completely different from the world of ours. So, what you believe to be true is only true with respect to your mind. Thus I argued nothing is a perfect one and No one is absolutely true. I said everything is relative.  

         

But he explained it in a different manner with pure psychology.

He said no one is correct and a perfect decision can never be made in any situation. He also gave an example. And I love that example.

         

Let us take a debate between two groups of people. One group is supporting for an idea and arguing that it is good. The other is opposing that idea by stating it as bad.   

Let say, both of the groups went to a common person to ask for a decision.

Now can anyone decide whether the idea is really good or bad as a common person?

But the condition is, “The decider should not be in either of the groups because he should be a common one”.

The answer is no. “The decision cannot be made by a common person”. The argument is as follows,

Let us take some number of people. In this total, a group is supporting an idea. The great thing is that, it also implies that the people who are not in the first group automatically allocated into the opposing group.

You can say, some of the people may be common, who supports for both 50-50.       
But think..

There is no use of the common people in this task. We need a decision. 

        When you need to take a decision, you don’t need a common person.

A common person is one who supports both groups 50-50 is moreover equivalent to a person who doesn’t support both of the groups. Simply they are useless in the debate. We don’t need to consider them.

Thus if you ask for a common person to make the decision, and suppose if he take a decision, "by the time he takes a decision, he will be allocated to either one of the groups". If the decision is to support, then he will be allocated to first group. Otherwise he will be classified to the second group. 
Thus he will be no more a common person. And his decision is useless, because he is on one side. 
The condition is that we need the decision from a common man.

So what is now? Again we are in a debate. 

It is always the ideas of one group will be against to the people in other group. And the common people are useless.

Thus we can come to the conclusion that "any decision can never be made as the truth".

Then what we think as the truth in our real life is “the idea of the majority ones”. The idea agreed by most of the people is considered to be the reality. Similar to the idea of the physical world. 
The world seen by most of the people was considered as the real and not the world of a blind or the world of snake (full of infrared things).

Thus the ultimate truth can never be achieved.  

Then who is right?